Gaetano Dongarra

Acid gas and metal emission rates during long‐lived basalt degassing at Stromboli Volcano

The discharge of acid gases and metals from Stromboli is determined from airborne and ground-based filter sampling of particulate matter in the volcanic plume, combined with COSPEC measurements of SO2 fluxes. Smaller particle sizes and high enrichment factors distinguish the most volatile elements (by order: S, Se, Br, Cl, Cd, Bi, In, As, Sb, Sn, F, Au, Pb, Cr, Cu) from those strictly (Fe, Mn, REE, Sc, Sr, Th, Ti, V) or mainly (Al, Ba, Ca, Co, K, Na, U) derived from volcanic ash. Time-averaged volatile fluxes show that Stromboli is a representative arc emittor, producing 1–2% of the global volcanic budget of sulfur, halogens and several trace metals, while 15–25% of volcanic emissions of Bi, Cd, Cs, Pb and Sn in southern Italy. Subaerial degassing of its S-Cl-rich shoshonitic magma over the last 2 ky of similar activity may have released as much copper and gold as is encountered in magma-derived high-sulfidation ore deposits.

Volcanic and anthropogenic contribution to heavy metal content in lichens from Mt. Etna and Vulcano island (Sicily).

Major and trace element concentrations were determined in two lichen species (Parmelia conspersa and Xanthoria calcicola) from the island of Vulcano and all around Mt. Etna. In both areas, the average concentrations of Al, Ca, Mg, Fe, Na, K, P and Ti are substantially greater than those of other elements. Several elements (Br, Pb, Sb, Au, Zn, Cu) resulted enriched with respect to the local substrates. The Br and Pb enrichment factors turned out to be the highest among those calculated in both areas. Data indicate that mixing between volcanic and automotive-produced particles clearly explains the range of Pb/Br shown by lichen samples. Sb is also enriched, revealing a geogenic origin at Vulcano and a prevailing anthropic origin at Mt. Etna. Distribution maps of the enrichment factors show a generalized enrichment of Au and Zn near Mt. Etna, whereas Cu appears to be enriched prevalently in the NE-SE area. The highest levels of Au and Cu at Vulcano occur E-SE from the craters, following the prevailing wind direction.

Concentration and reference interval of trace elements in human hair from students living in Palermo, Sicily (Italy)

Trace element contents in specimens of hair collected from 137 children aged 11-13 years old, living in Palermo (Sicily, Italy) were determined by ICP-MS. This work reports analytical data for the following 19 elements: Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, U, V and Zn. The most abundant chemical elements were zinc and copper (Zn > Cu), with concentrations exceeding 10 μg/g (Zn = 189.2 μg/g; Cu = 22.9 μg/g). Other elements with concentrations greater than 1 μg/g were, in order of abundance, Al>Sr>Ba>Pb. The remaining elements were all below 1 μg/g. The average elemental concentrations in hair were statistically compared by Kolmogorov-Smirnovs test taking childrens gender into account. Al, Ba, Cr, Li, Rb, Sb, Sr, V and Zn were statistically different according to gender, with significance p < 0.001. This study thus confirms the need for hair analysis to differentiate female data from those of males. IUPAC coverage intervals and coverage uncertainties for trace elements in the analysed hair samples are also reported.

Degassing of Trace Volatile Metals During the 2001 Eruption of Etna

This paper provides new data on sulfur, halogens, and minor and trace metal contents in airborne particulate matter from the Mt. Etna volcanic plume. Aerosol samples were collected by conventional filtration techniques before and during the summer 2001 eruption, in order to investigate relations between plume chemistry and volcano dynamics. Data analysis reveals that abundances of trace metals in the plume result from mixing of erosive and volatile components. The former is responsible for the contents of rare earth elements (REE), Ca, Ba, Sr, Ti, Sc, Y, Hf and Th; the latter contributes significantly to the abundance of Cs, Rb, Na and K, probably transported in the plume as metal halides, and Cd, Pb, Zn, Ge, Te, Mo, Re, Se, Sb, Sn, In, Bi, Tl, Cu and Au, associated with sulfur in plume particles. Enrichment factors show that plume particulate matter from the Monti Carcarazzi vent, which opened on the southern flank of the volcano in July 2001, is typically depleted in volatile trace elements with respect to the output from the summit crater, suggesting the secondary nature of the outpouring lavas. The decreasing trend observed throughout the eruption in the enrichment factors of most trace metals probably indicates a small-volume batch of magma with limited feed from depth.

Occurrence of platinum, palladium and gold in pine needles of Pinus pinea L. from the city of Palermo (Italy)

Abstract Preliminary data on the presence of Pt, Pd and Au in airborne particulate matter from the urban area of Palermo (Sicily, Italy) are presented. They were obtained by analysing 40 samples of pine needles (Pinus pinea L.) collected in and around the city. Observed concentrations range from 1 to 102 μg/kg for Pt, 1 to 45 μg/kg for Pd and 22 to 776 μg/kg for Au. Platinum and Pd concentrations in pine needles are up to two orders of magnitude higher than their crustal abundances. They exhibit a high statistical correlation (R2=0.74) which suggests a common origin. Precious metal concentrations measured within the city centre are much higher than those occurring outside the town. The distribution patterns of Pt and Pd in the study area are compared to the distributions of Au and Pb. Gold is enriched at the same sites where Pt and Pd are enriched, while Pb shows some discrepancies. The most probable local source of all of these elements is traffic. Average Pt and Pd emissions in the city area are estimated to be about 136 and 273 g/a, respectively. This study supports the use of pine needles as biomonitors of PGE in the environment.

Trace elements in the thermal groundwaters of Vulcano Island (Sicily)

Abstract The chemical concentrations of many trace elements that have never before been examined in Vulcano Island groundwaters are reported. Chemical data indicate that rock composition is not the only factor determining the metal content in the aqueous system. The observed concentrations depend mainly on: (1) the chemical composition of the host rocks; (2) the chemical–physical conditions of the weathering solution (temperature, acidity, redox conditions); (3) input of magmatic gases; (4) adsorption of metal ions on oxide particles, formation of soluble complexes and/or precipitation of solid phases. Chloride complexes in solution are of minimal significance for all elements with the exception of Cd, whereas carbonate complexes are important for Pb, UO 2 , Zn and Ni. Temperature and trace element distribution maps are also presented.

Chemical and isotopic characterization of the gases of Mount Etna (Italy)

Abstract In the period 1990–1995, 43 samples of dissolved gases in groundwaters (wells, springs and drainage galleries) and 64 samples of free gases (fumaroles, bubbling and soil gases) from the Mount Etna area were collected and analysed. Isotopic analyses were also carried out of both the carbon of the CO 2 in free gases and dissolved inorganic carbon (DIC) in the waters. The chemical composition of the gases depends on the relative abundances of three interacting components. These are gases of (1) atmospheric origin enriched in O 2 and N 2 , present almost exclusively in dissolved gases, (2) deep origin enriched in CO 2 , prevalent in the majority of cases, and (3) more superficial origin enriched in CH 4 , prevailing in peripheral areas. The isotopic composition of CO 2 carbon confirms its mantle origin with either thermometamorphic CO 2 contributions or modifications due to interaction with hot waters.

Isotope composition of rain water, well water and fumarole steam on the Island of Vulcano, and their implications for volcanic surveillance

Abstract Water samples from eight wells in the Vulcano Porto area and fumarole steam from the crater of Vulcano (Southern Italy) were collected at monthly intervals over a two-year period from February 1987 to January 1989. Samples of bulk precipitation were also collected in three points at Vulcano Porto and Vulcano Piano (island of Vulcano) and Castroreale (Tyrrhenian coast of Sicily), again at monthly intervals. The weighted mean isotopic composition of rain water on Vulcano is δ D =−32‰ , and δ D 18 O =−6.4‰ . Results for well waters tend to support the existence of at least two water bodies: one of purely meteoric water and the other of brackish thermal water. An intermediate water body, probably the result of mixing of the other two, was also recognized. The isotope composition of fumarolic steam from the crater suggests the mixed contribution of both sea and rain waters, although mixing is not the only process occurring. The existence of a deep marine-brine body is inferred, characterized by δD and δ18O values more positive than those of Mediterranean sea water. A close relationship, indicating common source effects, is shown by temporal isotopic variations at some wells and the fumarolic steam, wich may be used for volcano survey at distance from the active crater.

Possible markers of traffic-related emissions

Looking for robust indicators of motor vehicle emissions it has been found that brake wear and linings are significant contributors of Cu, Mo and Sb to air particulate matter. These trace elements, whose mutual ratios in airborne particulate matter resulted quite different from those in crustal material, appear to be available fingerprinting tools to identify the contribution of on-road vehicles to traffic-derived particulate matter. In this study, the results of analytical determinations of Cu, Mo and Sb on PM10, PM2.5, vegetation and brake dust samples, together with gas (CO, NOx) concentrations, are discussed. Highly significant correlations among Cu, Sb and Mo were observed in particulate matter from Palermo and between Cu–Sb and Cu–Mo at Catania. Further significant positive correlations have been found in pine needles from Palermo, Gela and in platanus leaves from Catania.

Trace elements in scalp hair of children chronically exposed to volcanic activity (Mt. Etna, Italy).

The aim of this survey was to use scalp hair as a biomonitor to evaluate the environmental exposure to metals and metalloids of schoolchildren living around the Mt. Etna area, and to verify whether the degree of human exposure to trace elements is subject to changes in local environmental factors. Twenty trace elements were determined in 376 samples of scalp hair from schoolboys (11-13 years old) of both genders, living in ten towns located around the volcanic area of Mt. Etna (Sicily). The results were compared with those (215 samples) from children living in areas of Sicily characterized by a different geological setting (reference site). As, U and V showed much higher concentrations at the volcanic site whereas Sr was particularly more abundant at the reference site. Linear Discriminant Analysis (LDA) indicated an Etna factor, made up of V, U and Mn, and a second factor, concerning the reference site, characterized by Ni and Sr, and to a lesser extent by Mo and Cd. Significant differences in element concentrations were also observed among three different sectors of Mt. Etna area. Young people living in the Mt. Etna area are naturally exposed to enhanced intakes of some metals (V, U, Mn) and non-metals (e.g., As) than individuals of the same age residing in other areas of Sicily, characterized by different lithologies and not influenced by volcanic activity. The petrographic nature of local rocks and the dispersion of the volcanic plume explain the differences, with ingestion of water and local food as the most probable exposure pathways.